He has now lodged 19 complaints about the conduct of bus drivers working for London General – part of The Go-Ahead Group – and 16 about Arriva.

When Stapleton (pictured) presses the blue button that is placed next to the wheelchair space, the driver should halt at the next stop and put down the ramp so that he can leave the bus.

But despite a siren sounding and an indicator light showing on their dashboard, drivers frequently drive off without putting down their ramp, with Stapleton still on board.

He said: “When the driver pulls away from the bus stop after ignoring my request, I normally shout, ‘Stop the bus! I pressed the blue button!’

“Most drivers don’t give any sort of apology for failing to deploy the ramp earlier.

“Some drivers don’t even stop the bus, and I’m forced to get off at the next stop.”

He said the number of times he had been forced to complain about London buses had roughly doubled every year since he started doing so three years ago, but he does not know why.

He said: “I can only [think]the bus drivers are getting lazier or less attentive. I really can’t explain it.

“There is no excuse. They are not paying attention, but it is part of their job to pay attention. I’m quite angry about it.”

Stapleton says that the complaints he has lodged with Transport for London (TfL) over the last three years have usually produced almost identical responses.

This means an apology for the “inconvenience and frustration” or “distress” he has experienced; confirmation that the driver should have pulled in at the next stop and put down the ramp when he pressed the button; and an assurance that the driver could face disciplinary action.

He said: “I’m really fed up with the bland responses I get from TfL when I send in complaints about this.

“I don’t want nice polite apologies: I want change, I want bus drivers to do their job properly, I want them to stop making my journeys stressful and upsetting.”

Transport for All, which campaigns for the rights of disabled and older people to travel in London, is now urging TfL to “speed up the renewal of their training programme”.

Faryal Velmi, director of Transport for All, said: “This is the tip of the iceberg. Transport for All receives regular complaints from disabled and older people facing the same situation.

“Many are so fed up with this that they’ve stopped reporting it.

“This adds to the stress that a journey can represent for many disabled and older people facing additional issues, such as broken ramps or the wheelchair priority space occupied by buggy users.”

Tony Akers, head of bus operations for TfL, said: “We’re happy to look into this and to work with the operators to see if anything can be improved.

“All complaints are investigated and we are constantly reminding our operators that drivers need to be on the lookout for disabled or vulnerable passengers, but if we can reasonably do more, we shall.

“Drivers are currently going through more training right now, precisely to highlight the needs of wheelchair-users.”

But Stapleton said in response: “I think it’s a case of ‘fine words, no actions’.

“The number of complaints I have raised about the blue buzzer issue is roughly doubling each year: the situation is getting worse, and it is affecting more and more wheelchair-users.

“It does suggest that TfL is not – whatever fine words it may utter in public – taking the issue seriously enough.”